Shelf-life of Chilled Muscle Tissue of the Common Carp (Cyprinus carpio L.) Packaged in Carbon Monoxide Enriched Modified Atmosphere

The aim was to study the effects of modified atmosphere packaging (MAP) consisting of 69% N-2, 25% CO2, 5% O-2 and 1% CO on sensory and chemical indicators (O-2 in MAP, pH, lipids, total volatile basic nitrogen TVBN, nitrogen-trimethylamine N-TMA, free fatty acids FFA, peroxides PV, malondialdehyde MDA) of carp (Cyprinus carpio, L.) fillets and compare them with fillets in simple packaging (control group). A total of 24 carp of 2.17 +/- 0.29 kg mean live weight were analyzed. The control fillets were analyzed on days 1, 2, 4, 7, 9 and 11. Fillets in MAP were analyzed on days 1, 4, 7, 9, 11, 14, 16 and 18. Fillets in MAP were pink red and the colour was stable (a carboxy-myoglobin complex), the control fillets were lighter with discolorations (from day 4). A change in the smell and consistency of fillets was observed starting on day 9 (MAP) and 4 (controls). Levels of pH in both types of samples fluctuated and no conclusive results were obtained. TVBN and N-TMA concentrations increased consistently upon fish aging. FFA concentrations on day 1 of monitoring were higher (p < 0.01) in MAP samples compared to the controls. Later, the production of these degradation products in the two types of packaging differed. MDA concentrations in MAP samples were lower (p < 0.01) throughout the experiment. MDA may be another suitable indicator for the determination of the intensity of fat oxidation.